WO2007131404A1

WO2007131404A1 - A method and device for realizing fast handover

Info

Publication number: WO2007131404A1
Application number: PCT/CN2007/000580
Authority: WO
Inventors: Hongfei Chen
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2006-05-15
Filing date: 2007-02-16
Publication date: 2007-11-22
Also published as: CN101051986B; CN101051986A

Abstract

A method for realizing fast handover includes: establishing static tunnel between PAR and NAR, and the previous mobile link being the first link, the new mobile link being the second link; before finishing binding update and after mobile node(MN) moving from the first link to the second link, the message involving the MN being transmitted through the static tunnel between the PAR and the NAR. A device for realizing fast handover is involved in the invention. In the invention, all the messages transmission involving MN could be performed in one static tunnel before finishing all binding update, no too much tunnels establishment and canceled messages emerges, and establishing abundant temporary tunnel is avoided, and the routers efficiency is improved.

Description

Method and device for realizing fast switching

This application claims to be filed on May 15, 2006, the Chinese Patent Office, Application No. 200610082243. X, entitled "A Method and Apparatus for Implementing Fast Switching," the priority of the Chinese Patent Application, the entire contents of which are incorporated by reference. Combined in this application.

TECHNICAL FIELD The present invention relates to the field of mobile communications, and in particular, to a method and apparatus for implementing fast handover in Mobile IPv6 (IP Version 6-IP Vers ion 6).

Background technique

With the development of network technology and the emergence of a large number of mobile terminals, such as laptops, PDAs, mobile phones, and in-vehicle devices, the mobile computing boom has been launched, and more and more users can pass various terminals. Connecting to the Internet through a public mobile wireless network at any location To address the needs of mobile services, Mobile IP (Mobi le IP) technology was introduced at the network level.

The basic principle of the Mobi le I P technology is to enable the mobile node to always use the initial IP address for IP communication during the mobile process, so as to ensure that the upper layer applications carried by the IP network layer maintain uninterrupted and continuable mobility.

At present, with the expansion of the network scale, IPv6 technology will gradually replace the current IPv4 (IP version 4-IP Version technology) based on its huge address space. IPv6-based Mobi le IP, namely Mobile IPv6 (Mobi le IPv6) technology, With the technical advantages of IPv6 and the improvement of Mobi le IPv4 technology, it is becoming a newcomer in the field of Mobi le IP, and it is gradually being widely applied.

Referring to Figure 1, for the mobile IPv6 topology, the home link and the foreign link are connected to the Internet through the home gateway and the foreign gateway respectively.

The mobile node (匪-Mobi le Node) is a communication node that can move from one network to another on the Internet and can keep the communication uninterrupted, and can communicate with the node as long as it knows the home address of the node.

A CN-Correspondence Node is a peer-to-peer node that is communicating with a mobile node, which can be mobile or fixed.

A home agent (HA-Home Agent) is a router that has a port connected to the home link of the mobile node. When the mobile node moves to the foreign link, it will be responsible for intercepting those sent to the mobile node. The packet of the home address is then forwarded to the mobile node using the tunneling mechanism and processes the current location information of the maintained mobile node.

Home Link refers to the default link of the mobile node and also the link with the same network prefix as the home address of the mobile node (such as the home IP address).

A foreign link (Foreign Link) refers to a link other than the home link whose network prefix is different from the network prefix of the mobile node's home address (such as the home IP address).

CoA: Care-of Address is the relevant IP address obtained when the mobile node moves to the foreign link. A mobile node can have multiple care-of addresses at the same time.

Referring to Figure 2, the working process of mobile IPv6 is as follows:

Step 101: When the mobile node connects to its home link, it will work in the same way as other fixed nodes. The mobile node is assigned an address on the home link, called the Home Address. This address is permanently assigned to this node, the same address as the fixed node. When the mobile node moves, its home address does not change. In Mobile IPv6, include a global unicast home address and network-local home address.

Step 102: The mobile node detects whether it has roamed to the foreign link through the IPv6 neighbor discovery mechanism. The IPv6 foreign gateway periodically sends a router advertisement message, which includes the prefix of the foreign link. After receiving the router advertisement message of the foreign gateway, the mobile node checks that the prefix of the foreign link is different from the prefix of the home link. It is considered to have roamed to the foreign link.

Step 103: If the mobile node finds that it has moved to the foreign link, it will obtain the relevant IP address on the foreign link through the stateful or stateless address auto-configuration process based on the received router announcement information. , called the care-of address (CoA-Care-of Addres s). At this time, the mobile node has both the home address and the care-of address.

Step 104: The mobile node registers its own care-of address with the "Binding Update" message to the home agent.

In addition to registering the care-of address with the "Binding Update" message to the home agent, the mobile node can also notify the communication partner of this care-of address through the "Binding Update" message registration. Before registration, the Return Routabi ty (return route reachable) detection process needs to be performed between the mobile node and the communication partner, that is, the mobile node first sends the Home Ini t Tes t message and the handover initialization test (Care- of Ini t Test ) message to the communication partner, the latter handles After that, return Home Tes t (Home Test) message and Care-of Tes t (Transfer Test) message to the mobile node.

Step 105: According to the object registered by the "Binding Update" message, the data packet is delivered in the following two forms:

a) Triangle routing:

If the mobile node's communication partner does not know its care-of address, it will send the data packet to the mobile node's home link according to the mobile node's home address, and then its home agent will intercept the data packet, and then according to the mobile node's current The care-of address, using the tunneling mechanism to forward these packets to the mobile node.

The message sent by the mobile node to the communication partner is also sent to the home agent through the reverse tunnel, and then forwarded to the communication partner by the home agent.

In this way, the data packets between the communication partner and the mobile node are transited by the home agent, so it is called the "triangular routing" mode.

b) Route optimization method:

If the communication partner knows the mobile node's care-of address through the "binding update", it will use the IPv6 routing header to directly transmit the packet to the mobile node. The first destination address of the packet is the handover address, and the second destination address is the home address. Therefore, the data packet will be sent directly to the mobile node in the foreign link, without the need to transit through the home agent.

In the opposite direction, the source address of the packet sent by the mobile node to the communication partner is the care-of address, and the home address is stored in the destination extension header of the packet. In this way, the data packet can also be sent to the home agent without going through the reverse tunnel, but sent directly to the communication partner.

In this way, the "triangular routing" mode is called the "route optimization" mode.

Since mobile IPv6 mobile nodes switch between networks, which causes service interruption, a fast handover method is described in the prior art. It introduces the following four new concepts:

· PAR: Previous Acces s Router, the access router of the mobile front link

• NAR: New Acces s Router, access router for the mobile link

• PCoA: Care-of address of the mobile front link

• NCoA: Care-of address of the link after the move

The central idea of the above existing fast switching method is to get the phase in advance before the "binding update" The information of the neighboring network generates the IP address of the neighboring network. Once the behavior of moving to the neighboring network occurs and the binding update is completed, a tunnel is established between the PAR and the MN to keep the traffic constant. See Figure 3 for the network structure. For the convenience of the following description, the network before the MN is moved is referred to as the network to which the PAR belongs, and the access router of the network is the PAR; the network after the MN is moved is referred to as the network to which the NAR belongs, and the access router of the network is the NAR.

Referring to Figure 4, the fast switching process is as follows:

Step 201: The MN sends an RtSolPr (Router Sol Authenticate for Proxy Advertisement) message to the PAR to request information about the neighboring network NAR. The timing of sending an RtSolPr message can be when an ND (Neighbor Di scover) message is sent.

Step 202: The PAR responds to the PrRtAdv (PrRtAdv: Proxy Router Advertisement), and the response message includes information about the neighboring network (that is, the network to which the NAR belongs), where the related information of the neighboring network includes at least Neighbor network access router (ie MR) information.

Step 203: If the returned neighbor network related information does not support fast handover, the fast handover process is terminated. If the returned neighbor network related information supports fast handover, the MN prepares to move to the NAR to generate the NCoA.

Step 204: When the MN is about to move to the NAR, send an FBU (Fass t Binding Update) message to the PAR.

Step 205: After receiving the FBU message, the PAR binds the PCoA and the NCoA, and then sends the HI (Handover).

Ini t iate, switch initialization) message to NAR, check if NCoA is legal.

Step 206: After receiving the HI, the NAR replies with a Hack (Handover Acknowledge) message to confirm its legality.

Step 207: The PAR returns a FBack (Fassing Binding Acknowledge) message to the MN and the NAR, and then saves the mapping relationship between the NCoA and the PCoA, establishes a PAR to the MN tunnel, and redirects the CN to the traffic to the tunnel.

Step 208: After the connection between the PAR and the PAR is moved to the NAR, before the binding update is completed, the NCoA is used as the source IP address, and the CN considers that the packet is illegal, and the PCoA is an illegal address in the network to which the NAR belongs. . According to the flow direction of the data packet, the following operations are performed separately: a) The traffic sent by the MN to the CN is encapsulated in the tunnel. The IP address of the inner IP header is PCoA, the destination address is the CN address, the source IP address of the outer IP address is NCoA, and the destination address is the PAR address. After the message passes the NAR, it will reach PAR. PAR^ will map the source address NCoA and PCoA. It knows that the message is a tunnel, removes the outer IP header, and forwards it to the CN with the inner IP header.

b) The traffic sent by the CN to the read. On the CN, the IP header source address is the CN address, and the destination address is PCoA. When the packet arrives at the PAR, the PAR encapsulates the packet according to the mapping between the NCoA and the PCoA. The source IP address of the outer IP address is the PAR address and the destination address is the NCoA address.

Step 209: After the binding update of the MN is completed, both the read and the PAR delete the tunnel. The MN then uses NCoA to communicate directly with the CN.

In the prior art, in step 207, 208, the tunnel is established between the PAR and the MN to ensure that the traffic before the NCoA binding update is completed, but the tunnel between the MN and the PAR is only after the MN moves to the network to which the NAR belongs. The MN is valid before the NCoA binding update is completed. The tunnel lifetime is very short. In a short period of time, the router's control module sends tunnel establishment and cancellation messages to the forwarding module. At the same time, when the number of MNs that are switched between the network to which the PAR belongs and the network to which the NAR belongs is large, there are a large number of tunnel establishment and cancellation messages between the control module and the forwarding module of the router, and the number of MNs on the router that need to be established and moved is the same. Tunneling, which causes router performance to degrade.

Summary of the invention

An object of the embodiments of the present invention is to provide a method and apparatus for implementing fast handover. After a mobile node moves to a new network and before a binding update is completed, the router does not need to generate a large number of temporary tunnels with a large number of MNs, so that packet transmission can be implemented. .

An embodiment of the present invention provides a method for implementing fast handover, where the method includes: establishing a static tunnel between an access router PAR of a mobile front link and an access router N AR of a mobile link, before the moving The link is a first link, and the mobile link is a second link; after the mobile node moves from the first link to the second link, before the binding update is completed, the PAR and the NAR are passed The static tunnel between the two transmits the message related to the mobile node.

An embodiment of the present invention provides a device for implementing fast handover, where the device includes a tunnel establishment module and a transmission module, where The tunnel establishment module is configured to establish a static tunnel between the access router PAR of the mobile front link and the access router NAR of the mobile link, where the mobile front link is the first link, and the mobile chain is The road is the second link;

The transmitting module is configured to pass the static tunnel between the PAR and the NAR to the mobile node after the mobile node moves from the first link to the second link, before the binding update is completed. The message is transmitted.

It can be seen from the foregoing technical solution that, in the embodiment of the present invention, since a static tunnel is established between the mobile forward link access router and the mobile link link access router, the related mobiles before all binding updates are completed are completed. The packet transmission of the node can be performed through the tunnel, and a large number of tunnel establishment and cancellation messages do not occur. Compared with the temporary tunnels of the same number of ports that need to be established and moved on the router in the prior art, the embodiment of the present invention provides The technical solution can greatly improve the efficiency of the router.

DRAWINGS

1 is a network topology diagram of a mobile IPV6 in the prior art;

2 is a flow chart of the operation of the mobile IPv6 in the prior art;

3 is a topology diagram of a mobile node access network in the prior art;

4 is a flow chart of a method for implementing fast switching in the prior art;

FIG. 5 is a flowchart of a method for implementing fast handover according to an embodiment of the present invention;

FIG. 6 is a structural diagram of an apparatus for implementing fast switching according to an embodiment of the present invention.

detailed description

In order to solve the problem that the PAR existing in the prior art and the large number of mobile nodes generate a temporary large number of tunnels, the embodiment of the present invention provides a method for implementing fast switching.

After the technical solution of the embodiment of the present invention moves to the NAR, the following steps are performed before the binding update is completed, so as to reduce the number of tunnels.

Referring to FIG. 5, it is a flowchart of a fast handover method according to an embodiment of the present invention, which includes the following steps:

Step 301: A static tunnel is established between the PAR and the NAR. The tunnel is established for a long time and does not need to be frequently established or deleted. The static tunnel can adopt various technologies, such as an IP tunnel, an IPSEC tunnel, an MPLS tunnel, and the like. As long as you move from the same PAR to the same NAR, no matter how many, Both use the static tunnel forwarding traffic between the same PAR and NAR. The source address encapsulated in the packet transmitted from the PAR to the NAR through the static tunnel is the PAR address, and the destination address is the NAR address. The source address encapsulated in the packet transmitted from the NAR through the static tunnel to the PAR is NAR address, destination address is PAR address.

Step 302: Establish a mapping relationship of the mobile node on the PAR and the NAR before the mobile node binds the update, and the content of the mapping relationship includes a mobile forward care-of address PCoA, a mobile link care-of address NCoA, and a Information about NAR and PAR at both ends of the tunnel. The specific steps are as follows: A) the mobile node sends a request message to the NAR through the PAR in the network to which the PAR belongs, and the NAR sends a response to the mobile node by using the PAR, where the response carries the address information of the NAR, and the mobile node The NCoA is generated according to the address information of the NAR. In addition, the PAR can also obtain the NAR address information from other servers. After the mobile node sends a request message to the PAR, the PAR can inform the mobile node of the MR address information obtained from other servers, and the mobile node generates the NAR address information according to the NAR address information. NCoA.

B) when the mobile node is about to move to the network to which the NAR belongs, the mobile node sends a request message including the NCoA to the PAR, and after receiving the request message, the PAR sends a request to the NAR to confirm whether the NCoA address is legal. a legality request message, where the legality request message carries a mapping relationship between the PCoA, the NCoA, the NAR address information, and the PAR address information; the NAR address information and the PAR address information may be respective IP addresses, or may be able to find The port address to the IP address.

0 after the NAR receives the legality request message requesting the validity of the request, the NAR

The PAR sends a validity confirmation message confirming the validity, and establishes a mapping relationship between the PCoA, the NCoA, the NAR address information, and the PAR address information.

D) The PAR establishes a mapping relationship between the PCoA, the NCoA, the NAR address, and the PAR address after receiving the validity confirmation message.

The mapping relationship corresponding to each MN is shown in Table 1:

匪 PCoA NCoA NAR PAR

MN1 10. 2. 2. 0 10. 1. 1. 0 10. 1. 0. 0 10. 2. 0. 0

MN2 10. 4. 2. 0 10. 3. 1. 0 10. 3. 0. 0 10. 4. 0. 0 Step 303: After the foregoing mapping relationship is established, before the mobile node moves to the network to which the NAR belongs, before the binding update is completed, the mobile node and the PAR/NAR perform the setting of the inner layer IP address according to the mapping relationship. The packet is encapsulated and transmitted through a static tunnel between the NAR and the PAR. Perform the following steps based on the different flows of the packets:

a) Traffic sent by the MN to the CN: In this embodiment, the MN1 in Table 1 is taken as an example. For the convenience of description, the packet encapsulated by the tunnel is called a tunnel packet, and is not encapsulated by the tunnel or has been decapsulated by the tunnel. The message is called an ordinary message.

Step al: 丽1 does not tunnel the ordinary message to be sent to the communication partner. The source IP address is NCoAlO. 1. 1. 0, the destination address is the CN address, and then sent.

Step a2: The ordinary message first arrives at the NAR, and the source address and the destination address of the original message are used as the inner layer address, that is, the source IP address of the inner layer IP header is NCoAl O. 1. 1. 0, and the destination address is CN. Address: The NAR uses the source address of the source NCo A to find the address of the PAR in the mapping table, and encapsulates the packet into a tunnel. The outer IP header of the tunnel packet is also The NAR address is 10. 1. 0. 0, and the destination address is PAR address 10. 2. 0. 0.

Step a3: After receiving the tunnel message, the PAR performs tunnel decapsulation to obtain an inner layer IP header source address NCoAl O. 1. 1. 0, and the destination address is a CN address, and the PCoA and NCo A in the mapping table are used. The mapping relationship converts the inner IP address source address NCoAl O. 1. 1. 0 into PCoAl O. 2. 2. 0, and sends the decapsulated ordinary packet to the CN.

In the above step a2, the NAR can also refer to the IP header source address of the common message NCoAlO. 1. 1. 0 to check the mapping table to obtain the corresponding PCoAl O. 2. 2. 0, using PCoAl O. 2. 2 0. Replace NCoAl O. 1. 1. 0 as the inner IP header source address, the inner IP header destination address is the destination address CN address of the packet, and then tunnel the packet according to the packet. IP address source address NCoAlO. 1. 1. 0 look up the mapping table to get the PAR address 10, 2. 0. 0, and set the outer IP header source address to NAR address 10. 1. 0. 0, destination address set The PAR address is 10. 2. 0. 0. In this way, in the above step a3, after the PAR receives the tunnel packet and performs tunnel decapsulation to obtain the inner layer IP header, the PAR does not need to perform IP header address processing, and can directly send the packet to the CN.

b) The flow rate of CN to Li: This embodiment takes Li 2 in Table 1 as an example.

Step bl: The ordinary 4 艮 message sent by CN to MN2, whose source address is CN address, and the destination address is PCoAlO. 4. 2. 0.

Step b2: After the traffic reaches the PAR, the PAR uses the source address and the destination address of the packet as the inner address, that is, the source IP address of the inner layer is the CN address, and the destination address is PCoAl O. 4. 2. 0. The PAR passes the packet destination address PCoAl O. 4. 2. Q finds the corresponding NAR address in the mapping relationship table, and encapsulates the packet in the tunnel. The outer IP header source address is PAR address 10. 4. 0. 0 , The destination address is the NAR address 10. 3. 0. 0. The encapsulated tunnel packet is sent to the NAR through a static tunnel between the PAR and the NAR.

Step b3: After receiving the tunnel message, the NAR performs tunnel decapsulation to obtain an ordinary packet whose inner IP address is a CN address and whose destination address is PCoAl O. 4. 2. 0, according to the purpose of the packet. Address PCoAl O. 4. 2. 0 Check the mapping relationship between PCoA and NCoA saved in the mapping table to get NCoAl O. 3. 1. 0, and set NCoAlO, 3. 1. 0 as the address of the inner IP header. Only sent to MN2. The relationship is corresponding to NCoAl O. 3. 1. 0, the inner IP header address is set to NCoAl O. 3. 1. 0, the inner IP header source address is set to the CN address, and the PAR passes the document. The address NCoA finds the address of the MR in the mapping table, and the packet is encapsulated in the tunnel. The source IP address of the outer IP address is 10.4, 0, and the destination address is the NAR address 10. 3. 0. 0, The tunnel message is then sent to the MN2 through the tunnel. In this way, in the above step b3, after receiving the tunnel packet, the NAR performs tunnel decapsulation to obtain an inner layer IP header, and does not need to perform IP header address processing, but can directly send the packet to 匪 2.

The method for implementing the fast handover according to the embodiment of the present invention further includes: after the completion of the binding update, the message is sent to notify the PAR and the MR, and the PAR and the NAR delete the mapping relationship between the PCoA and the NCoA. A message can be customized during the implementation process. As long as PAR and NAR know that Li has completed the binding update, PAR and NAR will forward the traffic packets related to the 按照 in the normal way. Therefore, the MN can only announce the completion of the binding update to the PAR and the NAR. As to whether the mapping relationship between the PCoA and the NCoA is deleted by the PAR and the NAR, the MN can be selected according to the specific situation.

At the same time, the aging mechanism of the mapping relationship between the NAR and the PAR is required. After a certain mapping is established, the mapping is not deleted by the packet for a certain period of time.

Based on the same inventive concept as the foregoing method for implementing fast switching, the present invention also provides a fast switching device. Referring to Figure 6, a schematic embodiment of the present invention provides a structural apparatus to achieve fast switching, in general terms, the apparatus comprising a tunnel establishing module 61 and transmitting module ^62, wherein, the delivery module 62 comprises establishing mapping sub Module 6, tunnel processing submodule 622 and forwarding sub-module 623. The internal structure of the device will be further described below in conjunction with its specific working principle.

The tunnel establishment module 61 is configured to establish a static tunnel between the access router PAR of the mobile front link and the access router NAR of the mobile link. In this embodiment, the mobile front link is the first link. After the mobile link is the second link.

The transmitting module 62 is configured to transmit a message related to the mobile node by using a static tunnel between the PAR and the MR after the mobile node moves from the first link to the second link and before the binding update is completed. Specifically, the mapping establishment sub-module 621 establishes a mapping relationship with the mobile node on the PAR and the NAR before the mobile node binding update, where the mapping relationship is specifically the mobile node's mobile forward care-of address PCoA, mobile The post-link care-of address NCoA and the mapping relationship between the NAR and PAR address information at both ends of the tunnel. The tunnel processing sub-module 622 encapsulates/decapsulates the packets entering and leaving the static tunnel based on the mapping relationship of the mobile node after the mobile node moves to the second link and before the binding update is completed.

Specifically, the tunnel processing submodule 622 specifically includes a NAR side tunnel processing unit and a PAR side tunnel processing unit. The NAR side tunnel processing unit uses the NAR address information and the PAR address information as the outer tunnel head to perform tunnel encapsulation on the received common message with the mobile node NCoA as the IP address source address of the temple port; or The PAR tunnel packet is tunnel decapsulated. The PAR side tunnel processing unit is configured to use the PAR address information and the NAR address information as the tunnel header for tunnel encapsulation of the received common packet with the mobile node PCoA as the destination address, or tunnel the tunnel packet from the NAR. Decapsulation.

A scheme is: the NAR-side tunnel processing unit replaces the sub-unit with the first address of the NAR side included, and based on the mapping relationship between the mobile node NCoA and the PCoA, the source IP address of the ordinary packet before the tunnel encapsulation is performed. The NCoA is replaced with the corresponding PCoA; the PAR-side tunnel processing unit replaces the sub-unit with the first address of the PAR side included therein, and based on the mapping relationship between the mobile node PCoA and the NCoA, the purpose of the ordinary packet before the tunnel encapsulation is performed. The IP address PCoA is replaced with the corresponding NCoA.

Another solution is: the PAR side tunnel processing unit replaces the subunit by the second address of the PAR side included therein, and based on the mapping relationship between the mobile node NCoA and the PCoA, the source of the ordinary packet after the tunnel decapsulation is performed. Replace the IP address NCoA with the corresponding PCoA; NAR side tunnel The channel processing unit replaces the sub-unit with the NAR-side second address included in the channel, and replaces the destination IP address PCoA of the ordinary packet after the tunnel decapsulation with the corresponding NCoA based on the mapping relationship between the mobile node NCoA and the PCoA. .

The message processed by the tunneling sub-module 622 is then forwarded by the forwarding sub-module 623. The forwarding submodule 623 specifically includes a tunnel forwarding unit and a regular forwarding unit. The tunnel forwarding unit tunnels the tunnel packet encapsulated by the tunnel processing sub-module 622 to the other party through the static tunnel between the PAR and the NAR; the conventional forwarding unit performs tunnel decapsulation on the tunnel processing sub-module 622. The subsequent ordinary message is forwarded according to the inner IP header information obtained after decapsulation.

Preferably, the device further includes a mapping deletion module, where the mapping deletion module is configured to delete the mapping relationship between the PAR and the mobile node established on the NAR after the mobile node is bound to the update. Of course, the mapping deletion module may not immediately delete the mapping relationship about the mobile node, as long as the PAR and the NAR are prohibited from using the mapping relationship after the mobile node binding update, for example, the mapping deletion module identifies the mapping relationship as prohibited or invalid. , it will not affect the normal message processing after the binding update.

The above are only the preferred embodiments of the present invention, and those skilled in the art should be included in the scope of the present invention within the scope of the present invention.

Claims

Rights request

A method for implementing fast handover, the method comprising: establishing a static tunnel between an access router PAR of a mobile front link and an access router NAR of a mobile back link, before the moving The link is a first link, and the mobile link is a second link; after the mobile node moves from the first link to the second link, before the binding update is completed, the PAR and the NAR are passed The static tunnel between the two transmits the message related to the mobile node.

The method according to claim 1, wherein the transmitting, by the static tunnel, the packet related to the mobile node comprises:

Establishing a mapping relationship with the mobile node on the PAR and the NAR before the mobile node binding update;

After the mobile node moves from the first link to the second link, before the binding update is completed, tunneling/decapsulating the packets entering or leaving the static tunnel is performed based on the mapping relationship of the mobile node;

Forwards the encapsulated/decapsulated packets of the tunnel.

The method according to claim 2, wherein the mapping relationship with respect to the mobile node is specifically a mobile forward care-of address PCoA, a mobile link care-of address NCoA, and the tunnel The mapping between the NAR and PAR address information of the terminal.

The method of claim 2, wherein: the forwarding, after the encapsulating/decapsulating the packet, specifically includes:

Passing through the tunnel encapsulation tunnel, the tunnel is forwarded to the other party through the static tunnel between the PAR and the NAR;

The ordinary packet that has been decapsulated by the tunnel is forwarded according to the inner IP header information obtained after decapsulation.

The method of claim 3, wherein the process of encapsulating/decapsulating the packets entering or leaving the static tunnel based on the mapping relationship of the mobile node includes: The NAR uses the NAR address information and the PAR address information as the outer tunnel header to encapsulate the received common packet with the mobile node NCoA as the source IP address of the packet, or tunnels the tunnel packet from the PAR. Package

The PAR tunnels the received packet with the destination address of the mobile node PCoA as the destination address by using the PAR address information and the NAR address information as the tunnel header; or tunnel decapsulation of the tunnel from the NAR.

The method according to claim 5, wherein the process of encapsulating/decapsulating the packets entering or leaving the static tunnel based on the mapping relationship of the mobile node further includes:

Based on the mapping relationship between the mobile node NCoA and the PCoA, the NAR replaces the source IP address NCoA of the common 艮 message before the tunnel encapsulation with the corresponding PCoA;

Based on the mapping relationship between the mobile node PCoA and the NCoA, the PAR replaces the destination IP address PCoA of the ordinary packet before the tunnel encapsulation with the corresponding NCoA.

The PAR replaces the source IP address NCoA of the ordinary packet after the tunnel decapsulation with the corresponding PCoA based on the mapping relationship between the mobile node NCoA and the PCoA;

The NAR replaces the destination IP address PCoA of the ordinary packet after the tunnel decapsulation with the corresponding NCoA based on the mapping relationship between the mobile node NCoA and the PCoA.

The method according to any one of claims 1 to 7, wherein the method further comprises:

After the mobile node binding update is completed, the PAR and the NAR receive an announcement message regarding the completion of the mobile node binding update.

The method according to any one of claims 2 to 7, wherein the specific process of establishing a mapping relationship between the PAR and the NAR on the mobile node comprises:

The mobile node ¾ PAR 'relevant to the network generates the ^NCoA;!

The NAR establishes a mapping relationship between PCoA, NCoA, NAR address information, and PAR address information;

The PAR establishes a mapping relationship between PCoA, NCoA. NAR address information and PAR address information.

The method for implementing the fast handover according to claim 9, wherein the establishing the mapping relationship by the NAR specifically includes:

Before the mobile node moves to the network to which the NAR belongs, the mobile node sends a request message including the NCoA to the PAR, and after receiving the request message, the PAR sends a request for validity to the NAR to confirm whether the NCoA address is legal. a message, the legality request message carries a mapping relationship between PCoA, NCoA, NAR address information, and PAR address information;

After receiving the legality request message, the NAR establishes a mapping relationship between PCoA, NCoA, NAR address information, and PAR address information.

The method for implementing the fast handover according to claim 10, wherein the process of establishing a mapping relationship after the NAR receives the legality request message further includes:

After receiving the legality request message, the NAR sends an acknowledgement NCoA legality confirmation message to the PAR;

Correspondingly, the process of establishing a mapping relationship by the PAR is specifically:

After receiving the legality confirmation message, the PAR establishes a mapping relationship between the PCoA, the NCoA, the NAR address information, and the PAR address information.

An apparatus for implementing fast switching, wherein the apparatus includes a tunnel establishment module and a transmission module, where

The tunnel establishment module is configured to establish a static tunnel between the access router PAR of the mobile front link and the access router NAR of the mobile link, where the mobile front link is the first link, and the mobile chain is The road is the second link;

The device according to claim 12, wherein the transmitting module comprises: a mapping establishing submodule, configured to establish, on the PAR and the NAR, the mobile node respectively before the mobile node binds the update Mapping relations;

a tunneling submodule, configured to encapsulate a packet entering and leaving the static tunnel based on a mapping relationship of the mobile node after the mobile node moves from the first link to the second link and before the binding update is completed. Decapsulation And a forwarding submodule, configured to forward the packet processed by the tunnel processing submodule.

The device according to claim 13, wherein the mapping relationship with respect to the mobile node is specifically a mobile forward care-of address PCoA, a mobile link care-of address NCoA, and the tunnel of the mobile node. The mapping between NAR and PAR address information at both ends.

The device according to claim 13, wherein the forwarding submodule specifically includes:

a tunnel forwarding unit, configured to forward a tunnel packet encapsulated by the tunnel processing sub-module to the other party through a static tunnel between the PAR and the NAR;

The conventional forwarding unit is configured to perform normal forwarding of the common IP packet obtained by decapsulating the tunneled sub-module according to the inner IP header information obtained after decapsulation.

The device according to claim 14, wherein the tunnel processing submodule comprises:

The NAR side tunnel processing unit is configured to use the NAR address information and the PAR address information as a tunnel header for tunnel encapsulation of the received common packet with the mobile node NCoA as the source IP address of the mobile node; or tunnel to the PAR The tunnel is decapsulated;

The PAR side tunnel processing unit is configured to use the PAR address information and the NAR address information as the tunnel header for tunnel encapsulation of the received common destination address of the mobile node PCoA, or to tunnel the packet from the NAR. Tunnel decapsulation.

17. Apparatus according to claim 16 wherein:

The NAR-side tunnel processing unit further includes a NAR-side first address replacement sub-unit, and replaces the source IP address NCoA of the common packet before the tunnel encapsulation with the corresponding one based on the mapping relationship between the mobile node NCoA and the PCoA. PCoA;

The PAR-side tunnel processing unit further includes a PAR-side first address replacement sub-unit, configured to replace the destination IP address PCoA of the ordinary packet before the tunnel encapsulation with the corresponding one based on the mapping relationship between the mobile node PCoA and the NCoA. NCoA.

18. Apparatus according to claim 16 wherein:

The PAR-side tunnel processing unit further includes a PAR-side second address replacement sub-unit, configured to replace the source IP address NCoA of the common packet after the tunnel decapsulation with the corresponding mapping based on the mapping relationship between the mobile node NCoA and the PCoA. PCoA; The NAR-side tunnel processing unit further includes a NAR-side second address replacement sub-unit for replacing the destination IP address PCoA of the ordinary packet after the tunnel decapsulation with the mapping relationship between the mobile node NCoA and the PCoA. NCoA. The device according to any one of claims 1 to 3, wherein the device further comprises a mapping deletion module, configured to delete the mobile node after the binding update A mapping relationship established on the PAR and the NAR with respect to the mobile node.